The invention relates to a read-convert device which read-converts the emergency brake command on railroad cars with different brake command systems, to operate the emergency brake at the same time in the situation where the railroad cars which are equipped with the brake systems of the different brake command systems are coupled so that they can operate together.
The prior art is described in Japanese Patent Publication No. 58-55023, and is illustrated in FIG. 6. This read-convert device 1 is installed, for example, on the electrical command system car E, which is connected to the air command system car A; and it consists of the discharge valve 2, on which the brake pipe BP of the air command system car is connected; the solenoid valve 3, which is installed in relation to this discharge valve 2; and the pressure switch 4, which is operated by the pressure in the brake pipe BP. The discharge valve 2 has the exhaust valve 2b, which opens and closes the exit 2a; and this exhaust valve 2b is installed on the bottom surface of the piston 2e, which divides the inside of the discharge vlave 2 into the upper chamber 2c and the lower chamber 2d, and the piston 2e is pushed by the spring 2f onto the valve seat of the exit 2a, to close the exit 2a. The above-mentioned lower chamber 2d connects the brake pipe BP.
With regard to the solenoid valve 3, the solenoid 3a is connected to ground and to the emergency brake command line EB for the emergency brake command of the electrical command system car, and has the flow inlet 3b which is connected to the brake pipe BP, flow outlet 3c which is connected to upper chamber 2c of the discharge valve 2, and the exit 3d which is open to the atmosphere.
The portion between the flow outlet 3c and the exit 3d is closed by the excitation of the solenoid 3a; and at the same time, flow inlet 3b and the flow outlet 3c are connected. By deenergizing the solenoid 3a, the portion between the flow inlet 3b and the flow outlet 3c is blocked; and at the same time, the flow outlet 3b is connected to the exit 3d.
The pressure switch 4 consists of the switching portion 4a, which opens and closes the emergency brake command line EB on the route to the brake system; and the drive portion 4b which moves the switch portion 4a to ON in response to a specified air pressure inside the brake pipe BP, and which turns it OFF as a result of the decrease in pressure.
The condition illustrated in the FIG. 6 illustrates the released brake, and the emergency brake command line EB is energized (electrically activated), the exit 2a of the discharge valve 2 is closed, the brake pipe BP is at a specified pressure (e.g. 5 kg/cm.sup.2), and the switch portion 4a of the pressure switch 4 is ON.
When the brake pipe BP is depressurized from this state (in response to the operation of the brake valve which is located in the operator's console of the air command system car into the emergency brake position), the emergency brake operates in the air command system car. Also in the electrical command system car, the emergency brake operates, since the pressure switch 4 of the read-convert device 1 goes OFF, so that the emergency brake command line EB becomes deenergized.
In addition, if the emergency switch (known as the conductor valve of the air command system car) was operated, or if the train is separted between the air command system car and the electrical command system car, or between air command system cars, the emergency brake operates not only for the air command system cars but also for the electrical command system car in the same manner as described above, since the brake pipe BP is depressurized.
In addition, when the brake controller in the operator's console of the electrical command system car is placed in the emergency position and the emergency brake command EB is switched to the deenergized state, the emergency brake operates in the electrical command system car, and the solenoid 3a of the solenoid valve 3 of the read-convert device 1 deenergizes so that the upper chamber 2c of the discharge valve 2 is open to the atmosphere; therefore, the piston 2e moves upward to open the exit 2a. and the brake pipe BP is depressurized, and therefore the emergency brake of the air command system car also operates.
Besides this, if the operator's emergency switch (conductor valve) of the electrical command system car is operated, or if the train is separted between the electrical command system cars and the air command system cars, or between the electrical command system cars, the emeregncy brake command line EB becomes deenergized, so that the read-convert device 1 operates, and the emergency brake operates not only on the electric command system cars but also on the air command system cars in the same manner as described above.
The emergency brake command read-convert device 1 of the prior art described above has the disadvantage that the emergency brake of the air command system car cannot be released by the operator from his console in the electrical command system car, after the emergency brake has been operated from the operator's console in the electrical command system car.
In other words, if the emergency brake has been applied by operating the brake control in the operator's console of the electrical command system car, and then afterward, the brake control is set in the release position, the pressure of brake pipe BP cannot be raised, so that the emergency brake of the air command system car cannot be released.
In addition, when the conductor valve and the conductor switch are operated in the operator's console of the electrical command system car, and then they are returned to the original position, the emergency brake cannot be released either.
In this case, it is possible to feed air into the brake pipe BP by operating the brake valve in the operator's console of the air command system car; however, the brake valve and/or the brake controller which is not used while the train is running are normally fixed, or the handle is removed, so that they cannot be operated.
Therefore, when the operator's console of the electrical command system car is being used, air cannot so easily be fed into the brake pipe BP. Therefore, it takes time to get the car running again.
The cause of this problem is the fact that the read-convert device 1 has the function of a mutual read-conversion of the emergency brake command, but it does not have the function of supplying air to the brake pipe BP.